Dental chair



March 13, 1962 w. D. TEAGUE, JR

DENTAL CHAIR 3 Sheets-Sheet 1 Filed Oct. 8, 1959 INVENTOR. WALTER 0. TEAGUE JR.

Mm ATTORNE S March 13, 1962 w. D. TEAGUE, JR

DENTAL CHAIR 3 Sheets-Sheet 3 Filed 001;. 8, 1959 INVENTOR. WALTER D. TEAGUE JR.

ATTORNEY 9m 3. mm. v

ited rites atent ware Filed Oct. 8, 1959, Ser. No. 845,281 13 Claims. (Cl. 297-327) My invention relates to dental chairs and to an arm rest adaptable for use more particularly in combination with a dental chair of a specific configuration as hereinbelow described.

My invention will be described primarily as an arm rest assembly to be attached to the specific dental chair hereinafter described, the combination with which is a part of my invention. However, the arm rest assembly may be attached to the arm rest support of any dental or other chair. The invention is also concerned with a configuration of the seating surface of a dental chair, the ease of raising and lowering the chair and the distribution of the body weight over the chair surface.

An object of my invention is to provide a slidable arm rest assembly for use in conjunction with a dental chair and seat frame which are of such shape as to render it difficult for the patient to alight from the dental chair when the arm rest is in a forward or normal position, said arm rest being retractable from its normal position to facilitate the ease with which a patient may leave the dental chair.

Another object of my invention is to provide a slidable arm rest in combination with a dental chair frame and seat, which dental chair frame may be pivoted on two pivots located on each side of a support for the chair frame at points which are substantially in a straight line with the center of gravity of the average patient sitting in the seat and the seat being acutely concave in the area where the buttocks of the patient rest so that upon sliding the arm rest backward from its normal position the ease with which a patient may get out of the dental chair is facilitated.

Another object of my invention is to provide a dental chair and seat frame particularly configurated for the comfort of the patient during operations and particularly designed for the comfort and ease of operation by a dentist desiring to sit down while operating upon a patient, all controls being accessible to the dentist when seated.

Still another object of my invention is to provide a shiftable arm rest on a dental chair which may be releasably locked in any one of a number of locking positions along the course of travel of the said arm rest by an individual standing or sitting either behind or at the side thereof.

My invention further contemplates a forwardly and rearwardly shiftable arm rest which may be releasably locked in any one of a number of positions with respect to a chair seat by a trigger mechanism in the rearward end of the arm rest enabling an individual to trigger the locking mechanism into an unlocked position and shift the arm rest either forward or rearward with a minimum of effort.

Other objects and advantages of my invention will be particularly set forth in the claims and will be apparent from the following description, when taken in connection with the accompanying drawings in which:

FIG. 1 is a side elevation of the seat, chair frame, chair support, slidable arm rest and tilting means, the solid lines indicate the seat and chair frame in a forward tilted position and the arm rest in a backward or rearward position and the dotted lines reflect the seat and chair frame in a backward tilted position and the arm rest in the forward and intermediate positions;

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FIG. 2 is a sectional view of FIG. 1 cut substantially through the middle of the seat and chair frame longitudinally thereof;

FIG. 3 is a top plan view of a small portion of the chair frame and the linkage between the tilting means and the chair frame, taken substantially on .lines 3-3 of FIG. 2 in the direction indicated by the arrows;

FIG. 4 is a sectional view taken substantially on the line 4-4 of FIG. 2 in the direction indicated by the arrows;

FIG. 5 is a diagrammatic drawing of the hydraulic system for the tilting means;

FIG. 6 is a top plan view of the arm rest with parts broken away and in fragmentary cross-section so as to illustrate the invention more clearly;

FIG. 7 is a side sectional view of the arm rest showing the arm rest and locking means therefor taken substantially on line 7-'7 of PEG. 6 in the direction indicated by the arrows;

FIG. 8 is a sectional view taken substantially on line 8-8 of FIG. 6 in the direction indicated by the arrows; and

FIG. 9 is a dotted line perspective view showing the arm rest in conjunction with a dental chair and showing a patient alighting from the chair with her right arm resting on one of the arm rests after the arm rest has been shifted to a rearward position.

Referring to FIG. 1, the dental chair 12, with which the arm rest, generally indicated by the numeral 13, is employed includes a seat or cushion 14 of relatively soft material supported by a rigid seat or chair frame generally indicated by the numeral 16 The seat frame 16 is in the form of a shell having upwardly extending walls on all sides thereof as indicated at 17 (FIG. 1) for the purpose of receiving and confining the seat cushion against movement.

The seat frame upon which the cushion M rests comprises a convexly curved leg rest section 18, a back rest section 25) and a concave intermediate or buttocks section 22 (FIG. 2). The curvature of the intermediate concave section 22 is acute and is adapted for the reception of the buttocks of the patient. The purpose of the acute curvature of the buttocks receiving section 22 is to anchor the patient in the chair and avoid any tendency for the patient to slide forward in the chair.

The seat frame is contoured as described so as to give the patient a relaxed feeling when sitting or reclining in the chair. The configuration is such that the body weight is more nearly evenly distributed over the length of the chair to avoid pressure points likely to interfere with the comfort of the patient. Because the dentist usually must adjust the chair inclination during the performance of operations on the patient, it is of critical importance that the patient be rigidly anchored in the chair. For example, if the chair is shifted forwardly with the buttocks unanchored, the patient will slide forward in the chair and upset the relationship of the head rest and the intermediate or buttocks section requiring the dentist to adjust the head rest each time the tilt of the chair is changed. The chair is designed for the practice of sit down" dentistry and all controls are located for convenience of access by the dentist when seated at the side or rear of the chair.

A rigid subframe, generally indicated by the numeral 24, is of a U-shaped cross-section (FIG. 4) with vertically extending arm rest supports 26. The chair frame 16 pivots on two pivots generally indicated by the numeral 23. The pivots 28 are located one on each of the supports 26. The means for tilting the chair 12 is generally indicated by the numeral 35) (FIG. 2). It will be observed that the chair frame 16 may be tilted forward and rearward by the tilting means 38 about the pivots 28, located on each arm rest support 26. Attached to the back of the chair frame 16 is a head rest, generally indicated by the numeral 32, which serves to support the head of the'patient seated in the dental chair 12. The specific head rest 32 is not a part of my invention, any one of a number of head rests being suitable for my purposes. However, the head rest should be adjustable forward and backward as indicated at 31 and up and down on a slide indicated at 35. This is conventional in head rest constructions.

Referring to FIG. 2 and FIG. 3, the tilting means 38 has a housing 33 mounted forward of the sub-frame 24. Within the housing is a hydraulic cylinder 34 containing a piston 36 (FIG. which is linked to the chair frame 16 at the location generally indicated by the numeral 38 on the exterior surface of the chair frame 16 at a location within the concavely curved intermediate section 22. The piston 36 is rigidly connected to a piston rod 48 which in turn is rigidly connected to a connecting piece 42; a nut 44 holds parts 40 and 42 together. The connecting piece 42 is transversely bored by a hole through which passes a hinge pin' 46 (see FIGS. 3 and 4). The hinge pin 46 likewise passes through two holes bored into parallel extending members 48 of the chair frame hinge 50 (see FIG. 4- and dotted lines in FIG. 3).

The chair frame hinge 58 is rigidly secured to the chair frame 16 by means of four bolts 47 which also pass through a hinge back-up plate 49 on the interior surface.

of the chair frame 16. The connecting piece 42 moves freely on the hinge pin 46 and is the pivot point between the linkage from the tilting means 38 and the chair frame hinge 59. The cylinder 36 is hydraulically driven by a hydraulic system shown diagrammatically in FIG. 5.

The oil in the hydraulic system enters at the position on.

the diagram indicated by the numeral 55 from a hydraulie power unit (not shown) located in the base. The base of the chair includes the usual pump, oil reservoir and piston for raising andlowering the chair.

Referring to FIG. 5, the levers 52 and 88 are shown in horizontal and normal positions when the chair 12 is.

at rest. The lever 52 is secured to a cylinder or tumbler 53 by a pin 51 which passes through a hole bored transversely of both the lever 52 and the tumbler 53. Likewise, the lever 88 is secured to a cylinder or tumbler 89 by means of a pin 99 passing transversely through a hole bored in both the lever 88 and the tumbler 89. When both the levers 52 and 88 are in a normal or horizontal position, as viewed inFIG. 5, six ball check valves, 56, 60, 78, 94, 9.6 and 100, the function of which will be hereinafter described, are seated by means of compression springs (not shown) and passage of oil in the hydraulic system at any of said valve positions is thereby prevented. When the levers 52 and 88 are horizontal, the piston136issecurely locked in place because oil cannottravel through either a pipe 66 or a pipe 72 which supply oil to and from cylinder 34. Tumblers 53 and 89 have, two cams each properly positioned in channels 58, 80,. 92 and 93, respectively, serving as actuators for ball check valves 56, 60, 78, 94, 96 and 100. When the forward lever 52 (see FIG. 1) is depressed, a mercury switch (notshown) is actuated and in turn a power unit (not shown) is started and hydraulic oil pressure is provided to position 55, and the attached tumbler 53 is rotated to a position where cam diameters at channel 58 and channel 80 open ball check valves 56 and 78 respectively. The oil passes through a fitting 54, past ballcheck 56 and around the channel 58. Ball check 60 is opened by the oil pressure, permitting oil to pass through a pipe 62, a joint 64, a pipe 66 and enters cylinder 34 through pipe 68. Because this is a double acting hydraulic cylinder, oil in the right end as viewed in FIG. 5 of the tilt cylinder 34 must escape before the piston 36 can travel to the right. The oil escapes through a pipe70 to pipe 72tl1rough a fitting 74; the'oil cannotpassthrough check valve which is closed, but through a passage 76 to the open ball check valve 78 around the channel 80, through a passage 82, along a pipe 84, through a tube 86 to the oil reservoir (not shown). Thus the piston 36 in the tilt cylinder 34 is driven to the right with respect to FIG. 5, causing the tilt cylinder shaft 40 to tilt the chair frame 16 (FIG. 2) to an upright position by means of the linkage above described.

When the backward tilt lever 88 is depressed the attached tumbler 89 is rotated to a position where cam diameters in channels 92 and 93 respectively open ball check valves 94 and 96. The power unit (not shown) has started an oil pressure to position 55. Oil is permitted to pass through fitting 54; oil cannot pass through check valve 56 which is closed, but across a passage 98, past ball check valve 96 and around channel 93. Oil pressure opens ball check valve 100, allowing oil to flow through fitting 74, into pipe 72, through pipe 70 to the right end of tilt cylinder 34. This oil pressure causes the piston 36 to travel to the left with respect to FIG. 5, forcing oil out of pipe 68 through tube 66, past fitting 64 into pipe 62, to the ball check valve 60 which is closed and into a pipe 102 through the open ball check valve 94, around channel 92, through a tube 104 to pipe 84 where the oil enters tube 86 and then into the oil reservoir (not shown). The forward tilt lever 52 and the backward tilt lever 88 are foot operated by the dentist using this machine.

Referring to FIG. 4, the chair frame 16 pivots on two pivots 28 supported by the arm rest supports 26 of subframe 24;

Each pivot 28 has a trunnion 162 comprising four sections, a flange section 171, a relatively large cylindrical section 166, an intermediate smaller cylindrical section 168 and a small knob section 170. The flange section 171 is rigidly secured to the support 26 by two screws 164. Section 166 fits snugly within a hole 158 bored transversely through the support 26. Section 168 is surrounded by a ball bearing 172;.said bearing fits rigidly inside of a bore 173 cut transversely in pivot support 174. Pivot support 174 is supported in a hole 175 cut in chair frame 16. A retaining ring 181 spaces bearing 172=and a reinforcing plate 176; said plate fits around the knob section 170 of trunnion 162. Two screws 177 secure plate 176 rigidly to pivot support 174; when threaded into holes in pivot support 174, screws 177 bring plate 176 into frictional contact with chairframe 16 on the right side thereof with respect to FIG. 4 and pivot support 174 into frictional contact with chair frame 16 on the left. Thus, it is seen that pivot support 174 is rigidly fastened to chair frame 16. There are two cover plates 168 having little flexible grippers. Said flexible grippers of the right hand cover plate with respect to FIG. 4'fit over and grip knob 170. Said grippers on the left cover plate grip a similar shaped knob (not shown) cast in the left end of trunnion 162 with respect to FIG. 4. The above described pivot means provide a means by which the chair frame may be easily pivoted with respect to the subframe 24. When the tilting means 30 tilt chair frame 16, ball bearing 172 is rotated on section 168 of trunnion 162.

As viewed in FIG. 4, the arm rest 13 is mounted on the uppermost end of the arm rest support 26. Now referring to FIGS. 6, 7 and 8, the arm rest 13 has a slide 178 to which is affixed a cushion or arm support 179 by means of three screws 180. The slide 178 may be shifted forward and backward on a track or arm rest guide 182 made of nylon or any suitable material. Guide 182 is attached to the arm rest support 26 by three screws 184. The guide 182 has a center groove 185 along which there are three slots 186 on each side of said center groove 185 (see FIG.

6). Arm rest 13 has a hand operatable lever 188 which is' rigidly mounted on a pivot stud 198 and rests on a washer 192 spacing lever 188 from slide 178. Pivot stud pivots in a'hole 193 out in slide 178. A handle 194 is rigidly connected to an inboardend'191 (FIG. 6)'ofthe lever 188. At the outboard end of lever 188, there is a locking stud or male locking member 198 rigidly attached to lever 188.

There is a right angle plate 200 rigidly connected to lever 188 by means of a rivet 202 and the locking stud 198 passing transversely through a hole (not shown) cut in said angle plate. There is a coil spring 204 one end of which engages plate 200; the other end of said spring engages a right angle plate 2%. Spring 2114 is aligned by a stud 2%5 rigidly connected to plate 200 and a stud 207 rigidly connected to plate 206. Plate-206 is rigidly afiixed to slide 128 (FIG. 8) by means of four rivets 208. The spring 204- opposes any counterclockwise motion of the lever 188 with respect to FIG. 6. An individual standing immediately behind or at the side of the dental chair may compress or trigger the handle 194 in a counterclockwise direction as viewed in FIG. 6 against the arm support 179. In response to said compression, there is an increased tension of the spring 204; the lever 188 pivots counterclockwise as viewed in FIG. 6 by means of stud 190; the locking stud 198 slides out of the slot 186; stud 205 engages stud 207. When in an engaging position, said studs furnish a means for stopping the locking stud 19 8 when it is exactly in the center of groove 185. A forward motion of the hand and arm of the individual triggering the handle 1% will cause the locking stud 198 to be moved respectively along the center groove 135 of the guide 182. The engagement of studs 295 and 217 permits locking stud 1% to be shifted forward or backward along groove 135 without interference from any of the slots 186, as said locking stud is shifted past said slots along its course of travel. When said individual has shifted the arm rest 13 to a position where the locking stud 198 is located at a position corresponding to one of the slots 186 where he desires to stop and lock the said arm rest, he merely releases the pressure being exerted against the handle 1%; the tension of spring 2114 rotates the lever in a clockwise direction with respect to FIG. 6 inserting the locking stud 198 into one of the slots 186. The lever 188 is spaced from slide 128 at the location where locking stud 1% transverses lever 188 by means of a washer 210.

A stop screw 212 is rigidly attached to the left end of slide 123 with respect to FIG. 6. When the arm support 179 and slide 178 are retracted to a backward position or to the right as viewed in FIGS. 6 and 7, the stop screw 212 will prevent the movement of the sliding arm rest 13 beyond the point where the stop screw 212 engages the arm rest guide 182.

I have used FIG. 9 in order to visually summarize the operation of the slidable arm rest 13 in combination with the dental chair 12. This shows a perspective View of a patient 214 alighting from the dental chair 12. The patient 214 has her right arm placed on the arm rest 13 when it is in a backward position. Having the arm rest 13 in this retracted position, facilities the ease with which said patient may alight from the dental chair 12. The slidable arm rest has a releasable locking means in combination with it so as to enable an individual standing behind the chair or at the side thereof to release said locking means, shift the arm rest 13 forward or backward and then lock the same into one of a number of pre-selected positions where there is slot into which the locking means may be locked.

While there has been shown and described the preferred form of invention, it will be apparent that various changes and modifications may be made therein without departing from the spirit of my invention as set forth in the appended claims.

I claim:

1. An armrest, adapted to be attached to a chair, comprising, in combination, a track connected to said chair, an armrest longer than said track and slidably mounted on said track, said track permitting only longitudinal movement of said armrest relative to said track, locking means intermediate said armrest and said track having hand control means located substantially at one end of and carried by said armrest, said locking means releasably locking said armrest in at least a forward position in which position the forward edge of said armrest is forward of said track and said hand control means is remote from the adjacent end of said track.

-2. An armrest in accordance with claim 1 in which said locking means comprises a select number of slots in said track, a locking member adapted to be received by said slots, and lever means extending from said hand control means to said locking member for controlling the movement of said locking member relative to said slots in response to movement of said hand control means.

3. An armrest in accordance with claim 2 including a pivot carried by said armrest between the locking member and hand control about which the lever rotates.

4. An armrest in accordance with claim 1 in which said locking means comprises a select number of slots in said track, a locking member adapted to be received by said slots, lever means extending from said hand control means to said locking member controlling the movement of said locking member relative to said slots in response to movement of said hand control means, a pivot carried by said armrest between the locking member and hand control about which the lever rotates, and pressure means exerting pressure against said lever tending to confine said locking member into one of said slots, thereby providing trigger unlocking action when a person applies force to said hand control means in opposition to said pressure means.

5. An armrest adapted to be attached to a chair, comprising, in combination, a track connected to said chair, an armrest longer than said track and slidably mounted thereon, said track permitting only longitudinal movement of said armrest relative to said track, locking means intermediate said armrest and said track having hand control means located substantially at the backward edge of and carried by said armrest, said locking means enabling releasably locking said armrest in at least a forward position in which the forward edge of said armrest is forward of said track and said hand control means is behind the backward edge of said track.

6. An armrest in accordance with claim 5 in which said locking means comprises a select number of slots in said track, a locking member adapted to be received by said slots, lever means extending from said hand control means to said locking member for controlling the movement of said locking member relative to said slots in response to movement of said hand control means, a pivot carried by said armrest between the locking memer and hand control about which the lever rotates, and pressure means exerting pressure against said lever tending to confine said locking member into said slots, thereby providing trigger unlocking action when a person applies force to said hand control means in opposition to said pressure means.

7. An armrest adapted to be attached to a chair comprising, in combination, a track connected to said chair, an armrest longer than said track and slidably mounted thereon, said track permitting only longitudinal movement of said armrest relative to said track, locking means intermediate said armrest and said track having hand control means located at substantially the backward edge of and carried by said armrest, said locking means comprising a select number of slots in said track, a locking member spaced from said hand control means longitudinally of said track and being adapted to be received by said slots, a lever extending longitudinally of said track and interconnecting said hand control means and locking member for transmitting locking motion from said hand control means to said locking member.

8. An armrest in accordance with claim 7 including a pivot carried by said armrest between the locking member and hand control about which the lever rotates and pressure means exerting pressure against said lever tending to confine said locking member into said slots, thereby providing trigger unlocking action when a person applies force to said hand control means in opposition to said pressure means.

9. A dental chair comprising, in combination, a chair frame, a seat carried by said frame, means for tilting said chair frame fore and aft so that a patient in the chair may sit substantially upright during an operation to be performed by a dentist or may be shifted to a substantially prone position by the dentist for performing other operations, said seat including a leg rest section, a back section and an intermediate section, said intermediate section being concavely curved to define a relatively deep. bucket for receiving the buttocks of the patient, armrest supports extending above and on both sides of said intermediate section, a track supported by at least one of said armrest supports, an armrest longer than said track and armrest support and slidably mounted on said track, said track permitting only longitudinal movement of said armrest relative to said track, looking means intermediate said armrest and said track having hand control means carried by said armrest, said locking means releasably locking said armrest in at least a forward position in'which position the forward edge of said armrest is forward of said track.

10. A dental chair in accordance with claim 9 in which said hand control means is located at the back of said armrest.

11. A dental chair in accordance with claim 10 in which saidlocking means comprises a select number of slots in said track, a locking member adapted to be received by said slots, and lever means extending from said hand control means to said locking member for controlling the movement of said locking member relative to saidslots in response to movement of said hand control means, thereby permitting'a person standing behind or at the side of the chair to control said locking means.

12. A dental chair in accordance with claim 9 in which said tilting means comprises, pivots located on each of said armrest supports at points which are in a straight line with the center of gravity of the chair frame, seat, and the average patient sitting in the seat, and automatic actuating means attached to said chair frame for pivoting said chair frame about said pivots.

13. A dental chair in. accordance with claim 9 in which said locking means comprises a select number of slots in said track, a locking member adapted to be received by said slots, lever means extending from said hand control means to said locking member controlling the movement ofsaid locking member relative to said slots in response to movement of said hand control means, a pivot carried by said armrest between the locking member and hand control about which the lever rotates, and pressure means exerting pressure against said lever tending to confine said locking member into one of said slots, thereby providing trigger unlocking action when a person applies force to said hand control means in opposition to said pressure means.

References (Zited in the file of this patent UNITED STATES PATENTS D. 181,048 Golden Sept. 24, 1957 1,721,027 Meyer July 16, 1929 2,606,596 Ziv Aug. 12, 1952 2,618,313 Piotraschke Nov. 18, 1952 2,672,917 Collura Mar. 23, 19 4 2,841,212. DeVos July 1, 19 8 2,871,928 Swenson Feb. 3, 19 9 2,900,011 Casey Aug. 18, 19 9 FOREIGN PATENTS 106,569 Australia Feb. 16, 1939 

